A non-immunological phospholipid-dependent coagulation inhibitor associated with IgGlambda-type multiple myeloma

Monoclonal Gammopathy of Thrombotic Significance

The current review provides an overview of the thrombotic risk observed in patients with MG who do not otherwise require treatment. We discuss clinical and biomarker studies that highlight the heterogenous hemostatic profile observed in these patients and how knowledge has evolved over the past 20 years. Biomarker studies suggest shared biologic features between multiple myeloma and monoclonal gammopathy of undetermined significance (MGUS), which involves both hypercoagulability and platelet activation. Hemostatic abnormalities identified in MGUS patients cannot be translated into clinical practice as they lack correlation to clinical events. The prothrombotic phenotype of MGUS patients has not been ascertained yet, but novel data on coagulation markers are promising. We also review rare conditions associated with the thrombogenic properties of the monoclonal protein that predispose to arterial, venous or microthrombotic events and demonstrate that the M-protein can be linked to clinically significant thrombotic events. Cryoglobulinemia, cryofibrinogenemia, cryo-crystaloglobulinemia and MG-related antiphospholipid syndrome are reviewed. We propose the new umbrella term "monoclonal gammopathy of thrombotic significance" (MGTS) to refer to significant, recurrent thrombotic events in patients with MGUS that provide a rationale for targeting the underlying plasma cell clone. Identifying MGUS patients at high risk for thrombotic events is currently a challenge.

Interference of M-protein on prothrombin time test - case report

The aim of this report was to present a case of interference on prothrombin time (PT) test that directed further laboratory diagnostics and resulted with final detection of monoclonal gammopathy in an 88-year old man. Routine coagulation testing during medical examination at Emergency Department revealed unmeasurable PT (< 7% activity) and activated partial thromboplastin time (aPTT) within reference range. After repeated sampling for coagulation testing, PT was unmeasurable again, as well as fibrinogen level (< 0.8 g/L), thrombin time (TT) was significantly prolonged (107 seconds) and aPTT was within reference range. In both plasma samples refrigerated at 4 ˚C overnight, white gelatinous precipitate was visible between the cell and plasma layers and the presence of monoclonal protein (M-protein) was suggested in our patient. Further laboratory diagnostics revealed total serum proteins at concentration of 123 g/L and the presence of M-protein IgG lambda (λ) at concentration of 47.1 g/L. These results suggested monoclonal gammopathy as an underlying pathophysiological condition in our patient. Activities of coagulation factors II, V, VII and X were within reference ranges or increased. These results and correction of unmeasurable PT result to 67% in mixing test with commercial normal plasma suggest in vitro rather than in vivo interference of M-protein on PT result. In contrast, significantly prolonged TT results in all analysed samples suggest impact of M-protein on this global coagulation test due to possible effect on fibrin polymerization.

Effect of serum monoclonal protein concentration on haemostasis in patients with multiple myeloma

Abnormalities in haemostasis are often detected in patients with multiple myeloma and the fundamental factors that lead to these abnormities are worthy of exploration. The objective of this study was to investigate bleeding diathesis and coagulopathy in different multiple myeloma types or stages and assess how paraprotein concentration contributes to differences in these conditions. Haemostasis screening tests and serum monoclonal protein (M protein) concentration were retrospectively analysed in 101 patients newly diagnosed with multiple myeloma from January 2012 to April 2014. No significant differences were found between bleeding diathesis and types or International Staging System (ISS) stages of multiple myeloma; however, prolonged thrombin time (TT) was found in most of patients (77.7%) and was positively related to light-chain concentration (P ≤ 0.01). Prolonged prothrombin time (PT) was more obvious in IgA and IgG-type multiple myeloma than in the light-chain type (P ≤ 0.01). With increased clinical staging, PT remarkably increased (P ≤ 0.01). M protein concentration was significantly higher in patients with prolonged PT than in those with normal PT (P ≤ 0.01). The D-dimer mean was significantly higher than normal (>0.5 μg/ml) (P ≤ 0.01). Fibrinogen was negatively related to M protein levels (P ≤ 0.01); however, there was no correlation between activated partial thromboplastin time (APTT) and multiple myeloma stages or types, M protein levels and serum light-chain concentration (P ≥ 0.05). Patients with light-chain type multiple myeloma were more likely to have prolonged TT than patients with other types. M protein levels had an obvious effect on PT. Prolonged PT was more common in IgA and IgG-type multiple myeloma. Abnormal haemostasis test results are not always accompanied by clinically apparent haemostatic complications.

Thrombosis in multiple myeloma

Multiple myeloma, as with other malignancies, has been associated with the development of venous thromboembolic events. Chemotherapy or steroids in combination with antiangiogenic agents can further enhance this risk. The identification of measurable factors associated with this prothrombotic state could help in the selection of patients who need antithrombotic prophylaxis. Malignancy-associated thrombophilic state, paraprotein-specific mechanisms and treatment-induced changes can explain the high rate of thrombosis in this cancer population. While the release of inflammatory cytokines induces high levels of factor VIII, von Willebrand factor and downregulate the protein C system, elevated plasma immunoglobulin can impair fibrinolysis. Strategies of thromboprophylaxis with low molecular weight heparin, warfarin or aspirin in patients treated with thalidomide/chemotherapy or lenalidomide and dexamethasone have shown efficacy. Early data indicate that the effect of low molecular weight heparin on multiple myeloma is not confined to the anticoagulant effect but could extend to survival; a similar positive trend in overall survival has also been reported in patients treated with aspirin.

Hematologic malignancies and thrombosis

Patients with hematologic malignancies have an increased risk of venous thromboembolism (VTE), particularly at diagnosis and during the treatment with chemotherapy, asparaginase or immunomodulatory drugs (IMiDs). A disease-dependent hypercoagulable condition associated with other risk factors like drugs, central venous catheter (CVC), immobility and infections are responsible for this high VTE rate. Thrombotic complications have a significant impact on morbidity and in some cases also on mortality of patients with onco-hematologic diseases, therefore thromboprophylaxis to prevent VTE in this setting is needed. However, thrombocytopenia and hemorrhagic complications pone many difficulties in the management of an anticoagulant or antiaggregant treatment in these patients. Recommendations from current guidelines are limited to multiple myeloma patients treated with thalidomide or lenalidomide associated with dexamethasone or chemotherapy, but hematological clinical departments should implement a policy for prevention and treatment of thromboembolic complications in hematologic malignancies.